Brake slack adjuster for vehicles



l 1 e24 752 Apnl 12, 1927. J. MITCHELL ET A BRAKQSLACK ADJUSTER FOR VEHICLES Filed May 24. 1926 Patented Apr. 12, 1 927. I UNITED stares,

JOHN MITCHELL AND 'J'oHN oncr'n'en'onen cossnxior LoNDoN, ENGLAND.

BRAKE SLACK ADJUSTER FOR vnrrrcnns.

Application filed May 24,1926, Serial No.1 111,348, and in Great. Britain Julyf 2i1925.

In U. S. Patent No. l,478,957, a brake:

I slack adjuster forrailway vehicles is de- I another tooth of the segment and lessens this the purpose described above. v

is preferably,

scribed in which aslotted and internally toothed segment is connected to the pullrods, and a pin, mounted in a lever arm connected' to. the-brake rods, or carried by one of thepull rods, engages between two of the teethof the segment. The arrangement is suchthat when,qowing to. the wear of the brake blocks and the'wheel'tire, the distance between their engaging surfacesin the ofi? condition. exceeds agiven amount, the pin on the release vof the brake, engage s with distance to a corresponding extent.

In the application of the brake to certain classes of vehicles the drawback is experienced that the' brake riggingin connec 'tion with the pin,.that is on thebrake side of the toothedsegment, moves so rapidly under the restoring forces of the brake gear, that thetime' is insufficient succeedingtooth to engage with the pin and thereby take up the slack of the brake blocks. v p

This drawback is obviated according to I the invention by the provision of'atwo-part movement which f is automatically imparted to a portion of the brake gear, during the return ofthe brake to the off first part of the movement which allows the brake blocks to 'beimoved fa predetermin'ed of the wheels,

of the movement is, however, retarded for This two-part movement effected according to this inventionby means of a sliding member, which is in frictional engagement with a pull rod, the-movement of; the pad ,being limited according to the amountof movement required to free the brake blocks from contact with the wheel tire, and-the amount of this movement being selected according to requirements- When applying the brake the pull rod and l the pad move together until further movement of the pad is prevented, after which the pull rod slides on the pad; When releasing the brake, the pullfrod and .the pad first travel together and the movement is free or unretarded, and is sufficient to free the brake blocks from the wheel tire.- Fur- I ther movement of the pad being nowprevented, the pull rod can only move toward to allow the next ,due to the weary position, the

in the form'of a pad, 3

, connected to the brake ,off pad, and as the consequently be in, frictional conthe surface of a roller mountedin a bracket secured to the frame ofthe vehicle. In order to limit-the movement of thepad relatively tothe rol-ler the former is provided at each, end with lugs or abutmentsso that when one or other of these comes into contact with the roller or bracket further movement 0fv the pad'in that direction is prevented: After: the completion of the movement ofthejpad, the pullvrod can continue to move and this motion will be retarded by the friction between'the pull rod andthe pad.

In another formof construction, the pad maybe pivoted to a lever which is also pity the vehicle. p v In a further construction. in. suchgcases oted in a bracket connectedto the frame of V where greater frictional resistance is required betweenthe pull rodand the pad, the pad may have upwardextenslons atthe top of 'which a cam with a balance weight is pivoted. Between the cam and the I topofthe 1 pull rod another pad is interposed. vThe balance weight rotates the cam and the pull rod is gripped between the two. pads.

i Theinvention is illustrated in the anneired drawings in which Fig.1 1s a general side elevation showing the devlce a'pplled to abrake mechanism. 9

Of the remaining views, which are all on a larger scale Fig. 2 is a side elevation of oneform of" construction of the device, and p j Fig.' 3 is acorresponding end elevation.

Fig. 4 is a side elevation ofan alternative form of construction, and v Fig. 5 isa corresponding end elevation. Fig. 6 is, a side elevationof athird form of construction. I 1 Referring first to Fig. 1,a is a slotted and internally toothedsegment, and b is a pin carried by the forked end 0 of the pull'rod cl and adapted to engage'between two of the teeth of the segment'a. A lever e is the pull rod 03 andalso to a second pull rod f. A brake rod 9 is pivotally position by; sliding over the .v friction between the rod and the pad canbe conside'rable,'suchmovement the pull. rodto co nstruction,-the I surface of the pull rod. .6 The lower surface of the pad bears against;

pivotally 1 connected to the lever e and is also connected to the brake block it. and i are hangers secured to the framework is of the vehicle.

Referring nowto Figs, .2 and 3, the device for imparting the required two-part movement to the brake block comprises a sliding member in the form of a pad Z, the upper surface of which is in frictional engagement with the lower surface of the pull rod (Z. The lowersurface of this pad Z bears against the surface of a roller m mounted by means of arivet n in a bracket 0 secured to the frame is of the vehicle. In order that the movements of the pad Z relatively to the roller we may be limited to a predetermined amount, this pad is formed at each end with lugs p, so that when one or other of these comes into contact with thesurface of the roller m further movement of the pad in that direction is prevented. Upon the completion of the movement of the pad the pull rodcan continue its movement in either direction,

but such movement will be retarded by the friction between the pull rod and the pad.

Referring now to the modified form of construction illustrated in Figs. 4 and 5 the pad Z is pivoted to a lever g which is pivoted to a bracket 0 secured to the frame is of the vehicle, the movement of the pad Z being limited by the movement of the lever g, these movements being limited by stops on the pad.

Fig. 6 illustrates a further modification designed for cases where greater frictional resistance is required between the pull rod and the pad.

In this case the pad Z is formed with an upward extension Z to which is pivoted a cam 3 provided with a balance weight [6. A second pad 14' is provided between the cam s and the upper surface of the 'pull rod (Z. The balance weight If serves to rotate the-cam s so that the pull rod d is gripped between the pads Z and u. I

Having thus described the nature of the said invention and thebest means we know of carrying the same into practical effect, we claim 1. A brake slack adjuster for railway vehicles comprising a slotted and internally toothed segment interposed between two parts of a brake gear, a pm on one of said :parts adapted to engage in the teeth of the segment, and means for imparting a twopart movement to aportion of the brake gear during the return of said gear to the off position.

2. A brake slack adjuster for railway vehicles comprising a slotted and internally toothed segment interposed between two parts of a brake gear, a pin on one of said whilst the second portion of said movement is suitably retarded.

3. A brake slack adjuster for railway v e-- hicles comprising a slotted and-internally toothed segment interposed between two'- parts of a brake gear, a pin on one of said= parts adapted'to engage 1n the teeth of the}- segmenhand means for imparting a two part movement to a portion of the brake gear-during the return ofsaid gear to the off position, said means comprising a slide member and a roller. I V I 4. A brake'slack adjuster for railway=ve-" hicles comprising a slotted and internally toothed segment interposed" between-two parts of a brake gear, a pin on one of said parts adapted to engage in the-teeth of the segment, and means for imparting a two part movement to a portion of the brake gear during the return of said gear to'the off position,

5. A brake slack adjuster 'forrailwayvehicles comprising a slotted and internally v said means comprising a slide" member in'the'form of a pad and aroller I toothed segment interposed between two parts of a brake gear, a pin on oneof said parts adapted to engage in the teethof the segment, and

part movement to a portion of the brake said gear'to the gear during the return of means for imparting a twooff position, Stlcl means comprising a slide member ofwh1ch the'upper surface 1s in contact with the pull rod of-the brake and of which the lower surface is in contact with a roller.

6. A brake slackadjuster for railway vehicles comprising a slotted and i'nter'r'i-ally toothed segment interposed between two parts of a brake 'gear,*a pin on one of'said parts adapted to engage in theteethof the segment, and means'forimparting a twopart movement to a portion of the brake gear during the returnof said gear to the off position, said means comprising a pad formed at each end with lugs, and a roller! In testimonywhereof we have signed'our names to thls spec1ficat1on..

JOHN MITCHELL; JOHN CECIL GEORGE GOSSEY. 7 

